A Highly Selective Fluorescent Chemosensor for Detecting Indium(III) with a Low Detection Limit and its Application

A highly selective chemosensor BHC ((E)-N-benzhydryl-2-((2-hydroxynaphthalen-1-yl)methylene)hydrazine-1-carbothioamide) for detecting indium(III) was synthesized. Sensor BHC can detect In(III) by a fluorescence turn-on method. The detection limit was analyzed to be 0.89 μM. Importantly, this value is the lowest among those previously known for fluorescent turn-on In(III) chemosensors. Based on the analytical methods like ESI-mass, Job plot, and theoretical calculations, the detection mechanism for In(III) was illustrated to be chelation-enhanced fluorescence (CHEF) effect. Additionally, sensor BHC was successfully applied to test strips.